The hydraulic struts partially support the weight of the car in addition to supplying damping. You would need to replace the springs with substantially higher rate springs to do the job right. Otherwise the tail end of the wagon will ride low, handling and tire life will be compromised, and of course that 1150lb load rating is gone. I've never heard of an aftermarket set of springs for the wagon.

The self leveling system provides a nice compromise between ride, handling, and load rating. It's probably also cheaper to repair it than replace it.

- JimY